Rotary core drill



Nov. 4, 1930.

mmvronsj ufghrgflfimasf ATTORNEY.

m. 1 m f ROTARY CORE DRILL Filed Nov. 2, 1927 J. E. EHGNS ET AL PatentedNov. 4 1930 UNITED STA S PATENT OFFICE .form nmnr snows, ornanmsnune,AND WILLIAM may norm, or noulsron,

'rnx'as ROTARY conn DRILL This invention relates generally-to drills 1particular reference to rotary core drills The primary object of theinvention 15 to 6 provide a drilling tool having a head of extremelysimple. construction but of durable character, which may effectively beused n earth boring operations wherein strata of various characters maybe encountered with little likelihood of damage or destruction to thehead or any of the parts thereof.

A further object is to provide a drill head of this character which hasits parts so assembled as to permit of repairs being quickly specialskill or tools, and which repairs or adjustments may be made at thescene of operations and without resorting to forwarding the head to amachine shop for such corrections.

A further object is to provide in a drill head of the charactergenerally specified, improved means for operating upon and gripin a coreas the latter passes through the flea whereby to insure holding of thecore against movement when the drill is moved from the well.

A still further object resides in the specific construction, assemblageand mode of operation of the core gripping member whereby to insureproper removal of the core at any desired time.

With these objects in View, together with others which will appear asthe description proceeds, the invention consists in the novelconstruction, combination and arrangement of parts, all as will bedescribed more fully hereinafter, illustrated in the drawings, andparticularly pointed out in the claim.

In the drawings:

Fig. 1 is a view taken longitudinally through a core drill headembodying the invention,

Fig. 2 is an enlarged view taken substanand easily made without theexercise of.

Application. filed November 2, i927. Serial No. 230,500.

tially upon line 2-2 of Fig. l and looking in the direction indicated bythe arrows,

Fig. 3 is a fragmentary view taken substantially upon line 33 of Fig. 2,and

Fig. 4 is a side elevation on a reduced scale, taken at right angles toFig. 1, illustrating the lower end of the head.

The drill head is represented generally at 4, and comprises an elongatedmetallic member of proper length and diameter, having its upper endreduced and threaded as shown to permit of screw threaded attachment tothe drill stem 5. The head is provided'with a central longitudinalopening 6 extending from the inner toward the outer end of the head, andthis opening is reduced in diam- .eter near its outer end to provide ashoulder 7 the reduced portion of the bore or opening constituting acoreway indicated at 8. This coreway, like the opening 6, is of circularformation. The opening 6 at the inner end of the head is internallythreaded to receive the external threads of a barrel 9, the latterhaving an internal diameter or coreway corresponding to the dimension ofthe coreway 8. When properly inserted in the opening 6, the coreway ofthe barrel will be axially aligned with the coreway 8. The-outer end ofthe barrel terminates short of the shoulder 7, so that a space isprovided between said shoulder and the adjacent terminal of the barrel.

Within thespace thus provided a gripper member for the core is arranged.This member is of such construction and operates in such manner with thedrilling process as to permit of free feeding of the core-withoutobstruction or interruption, yet operates in such manner that uponwithdrawal of the head the core is bitten or broken and held againstdropping out upon removal of the tool; In obtaining these results, weemploy a core gripper capable of freely rotating within the head andhaving limited longitudinal movement. The member employed com- 90 prisesan annular member,- ring or column indicated at 10, of slightly smallerexternal diameter than the internal diameter of the opening 6, andhaving an internal diameter corresponding to the diameter of the coreway8. This annular member is provided at proper intervals around itsperiphery with rollers or anti-friction members 11 which engage theinner wall in the opening 6. The height or thickness of the collar 10 isslightly less than the distance between the shoulder 7 and the adjacentend of the barrel 9. The distance between these elements may be variedas desired to increase or diminish the degrees of longitudinal travel ofthe collar 10. In the present instance, but little play is permitted thecollar l0,'as the distance between the end of the barrel-and theshoulder 7 is relatively short.

The collar or annulus carries a plurality of grippers capable ofengaging and firmly holding the core as it passes through the column.These grippers in the present instance comprise pawls or dogs 12 pivotedat their inner ends as at 13 within the collar and extending normallyinto the coreway within the collar. These dogs are set in recesses .14in the inner face of the collar, and these recesses are so shaped as topermit the free ends of the dogs to swing away from the axis of thecollar in an u ward direction. Each dog has a toe 15 at its innerextremity to seat against a shoulder in the collar to limit the inwardswinging movement of the dogs.

There may be an desired numbr of pawls or dogs 12 carried y the collar,and it is preferred that they be disposed radially of the annular member10.

The head 4 is provided near its lower end with bottom and side cuttersfor operation properly upon earth or rock in drilling the hole. Thelowermost of these cutters 16 are of preferably frusto conical formationand are mounted in the end of the head at an angle to the axis thereof.These cutters have their inner edges disposed substantially in alignmentwith the outer edges of the coreway, so that in rotary cuttingoperations a smooth core will be formed to pass into the coreway.Disposed at substantially right angles to the cutter 16 and elevatedslightly therefrom so as to protrude beyond the sides of the head arecutters 16'. These cutters 16-16 facilitate penetration as rotarymovement is applied to the head and clears the way as downwardprogression is made. Each cutter is referably supported upon a bearingbolt 17 t readed at its innerextremity into the head so as to be capableof being easily removed when required, and washers 18 are used in theassembly to minimize friction and to prevent jamming of the cutters. Inthe sides of the head at a point substantially re mote from the lowerend thereof clearance cutters 19 are mounted in a manner similar to thecutters 16--16v and for purposes well understood. The head is equippedwith ducts 21 leading from the upper end of the head to the cutters atthe lower end thereof, and branch ducts 22 communicate with therecesse's in which cutters 19 are mounted. These ducts permit of properlubrication of the rotating cutters, as will be readily understood.

In operation, the head is given rotary drilling movement, and thecutters 16 and 16 penetrate the earth and clear the way forthe head. Thecore passes upwardly through the coreway 8, and upon engagement with thedogs 12 forces them outwardly so as to pass into the coreway ofthe-barrel 9. Free passageof the core through the collar is permitted byreason of the restricting movement of the dogs as well as the mobilityof the collar both longitudinally and rotatably. This movement of thecollar permits of the free passage of the core with the least possibledanger of breakage of the same. When it is desired to remove the drill,upward movement applied to the drill stem will cause the head to movesimilarly, whereupon the action of the pawls in grippinig engagementwith the core causesthe free ends of the pawls to bite into the core andsever the same at their point of engagement therewith. The downwardmovement to a slight degree permitted in the collar facilitates thiscutting-elf operation. The core may then be removed from the barrel inthe usual manner.

By constructing the head and its assembled parts in this manner, it isapparent that the head is considerably strengthened and will thereforewithstand excess pressures with a minimum of opportunity forbreakage orderangement of any of the parts. The drilling operation may be conductedmore rapidly than has heretofore been possible, and the constructionobviates the necessity of aspirators or check valves in the core barrel.The assemblage is such that in case of wear of the parts they may beeasily replaced without the exercise of-special skill or tools, andreplacement of broken or worn cutters may be made, if desired, withoutdetaching the head from the drill stem.

While the foregoing is a description of the Having thus described ourinvention, we

claim:

In a cutter, a head having a coreway therein, a collar slidableloiigitudinally'therein, the said collar having longitudinally disingrelatively deep at their lower ends, a dog pivoted at its lower end inthe deeper portion of each of said recesses, the bottom walls of saidrecesses inclining in an upward .125 ppsed recesses in its inner face,said recesses direction toward the axis of said collar to receive saiddogs for a substantial part of their length and to maintain the sameinclined toward the axis of said collar, said dogs of slightly greaterlength than their recesses so that their free ends project beyond theupper end of said collar, and a toe on each dog to engage with itsrespective bottom wall to limit the inward swinging movement of the dog.

In testimony whereof we hereby afiix our signatures.

JOHN ELGIN SHOWS. WILLIAM TRACY DUNN.

